But the official said it was not clear that the required two-thirds majority would vote to leave the ICC.

The BBC's Emmanuel Igunza in Addis Ababa says Rwanda is one of the countries pushing for a rethinking of the relationship between Africa and the ICC.

"It is not only the case of Kenya," Rwanda's AU ambassador Joseph Nsengimana told the BBC.

"We have seen international justice is becoming more and more a political matter," he said.

The AU has called for the trials of Kenya's leaders to be sent back to Kenya.

The cases were only referred to the ICC after Kenyan politicians failed to set up special tribunals to prosecute those responsible for the violence.

In a letter sent to the ICC on 10 September - the day Mr Ruto's trial began, the AU argued that while he was in The Hague, President Kenyatta would not be able to leave the country to attend other meetings, such as forthcoming meetings at the UN and with the European Union.

The ICC judges have already agreed that the two trials should not be held at the same time, as Kenya's constitution requires that one of its leaders be present in the country at all times.

The ICC has responded to the AU letter by saying that the court's presidency does not have the powers to rule on ongoing cases and that this and any request to send the cases back to Kenya should be made directly to the judges.

The BBC's Odhiambo Joseph in Kenya's capital, Nairobi, says the ICC proceedings are being closely followed in the East African nation but are dividing people along political and ethnic lines.

Mr Ruto and President Kenyatta were elected in March.

They used their prosecutions by the ICC to bolster their campaign by portraying them as foreign interference in domestic affairs.

Mr Ruto is the first serving official to appear at the ICC.

The ICC was set up in 2002 to prosecute crimes against humanity, war crimes and genocide.

All the eight cases it is currently investigating are in Africa.

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Media captionKenya's Foreign Minister Amina Mohamed says President Uhuru Kenyatta and Deputy President William Ruto should not face trial